NCERT Exemplar Solutions
Class 7 - Mathematics
Unit 7: Comparing Quantities

Complete NCERT Exemplar Solutions for Class 7 - Unit 7: Comparing Quantities with answers and step by step solutions.

Multiple Choice Questions

In questions 1 to 23, there are four options out of which one is correct. Write the correct one.

Question.  1

20% of 700 m is

(a)

(a) 560 m

(b)

(b) 70 m

(c)

(c) 210 m

(d)

(d) 140 m

Open

Question.  2

Gayatri’s income is ₹ 1,60,000 per year. She pays 15% of this as house rent and 10% of the remainder on her child’s education. The money left with her is

(a)

(a) ₹ 136000

(b)

(b) ₹ 120000

(c)

(c) ₹ 122400

(d)

(d) ₹ 14000

Open

Question.  3

The ratio of Fatima’s income to her savings is 4 : 1. The percentage of money saved by her is :

(a)

(a) 20%

(b)

(b) 25%

(c)

(c) 40%

(d)

(d) 80%

Open

Question.  4

0.07 is equal to

(a)

(a) 70%

(b)

(b) 7%

(c)

(c) 0.7%

(d)

(d) 0.07%

Open

Question.  5

In a scout camp, 40% of the scouts were from Gujarat State and 20% of these were from Ahmedabad. The percentage of scouts in the camp from Ahmedabad is:

(a)

(a) 25

(b)

(b) 32.5

(c)

(c) 8

(d)

(d) 50

Open

Question.  6

What percent of ₹ 4500 is ₹ 9000?

(a)

(a) 200

(b)

(b) 1/2

(c)

(c) 2

(d)

(d) 50

Open

Question.  7

5.2 is equal to

(a)

(a) 52%

(b)

(b) 5.2%

(c)

(c) 520%

(d)

(d) 0.52%

Open

Question.  8

The ratio 3 : 8 is equal to

(a)

(a) 3.75%

(b)

(b) 37.5%

(c)

(c) 0.375%

(d)

(d) 267%

Open

Question.  9

225% is equal to

(a)

(a) 9 : 4

(b)

(b) 4 : 9

(c)

(c) 3 : 2

(d)

(d) 2 : 3

Open

Question.  10

A bicycle is purchased for ₹ 1800 and is sold at a profit of 12%. Its selling price is

(a)

(a) ₹ 1584

(b)

(b) ₹ 2016

(c)

(c) ₹ 1788

(d)

(d) ₹ 1812

Open

Question.  11

A cricket bat was purchased for ₹ 800 and was sold for ₹ 1600. Then profit earned is

(a)

(a) 100%

(b)

(b) 64%

(c)

(c) 50%

(d)

(d) 60%

Open

Question.  12

A farmer bought a buffalo for ₹ 44000 and a cow for ₹ 18000. He sold the buffalo at a loss of 5% but made a profit of 10% on the cow. The net result of the transaction is

(a)

(a) loss of ₹ 200

(b)

(b) profit of ₹ 400

(c)

(c) loss of ₹ 400

(d)

(d) profit of ₹ 200

Open

Question.  13

If Mohan’s income is 25% more than Raman’s income, then Raman’s income is less than Mohan’s income by

(a)

(a) 25%

(b)

(b) 80%

(c)

(c) 20%

(d)

(d) 75%

Open

Question.  14

The interest on ₹ 30000 for 3 years at the rate of 15% per annum is

(a)

(a) ₹ 4500

(b)

(b) ₹ 9000

(c)

(c) ₹ 18000

(d)

(d) ₹ 13500

Open

Question.  15

Amount received on ₹ 3000 for 2 years at the rate of 11% per annum is

(a)

(a) ₹ 2340

(b)

(b) ₹ 3660

(c)

(c) ₹ 4320

(d)

(d) ₹ 3330

Open

Question.  16

Interest on ₹ 12000 for 1 month at the rate of 10 % per annum is

(a)

(a) ₹ 1200

(b)

(b) ₹ 600

(c)

(c) ₹ 100

(d)

(d) ₹ 12100

Open

Question.  17

Rajni and Mohini deposited ₹ 3000 and ₹ 4000 in a company at the rate of 10% per annum for 3 years and 2 1/2 years respectively. The difference of the amounts received by them will be

(a)

(a) ₹ 100

(b)

(b) ₹ 1000

(c)

(c) ₹ 900

(d)

(d) ₹ 1100

Open

Question.  18

If 90% of x is 315 km, then the value of x is

(a)

(a) 325 km

(b)

(b) 350 km

(c)

(c) 405 km

(d)

(d) 340 km

Open

Question.  19

On selling an article for ₹ 329, a dealer lost 6%. The cost price of the article is

(a)

(a) ₹ 310.37

(b)

(b) ₹ 348.74

(c)

(c) ₹ 335

(d)

(d) ₹ 350

Open

Question.  20

\(\dfrac{25\% \text{ of } 50\% \text{ of } 100\%}{25 \times 50}\) is equal to

(a)

(a) 1.1%

(b)

(b) 0.1%

(c)

(c) 0.01%

(d)

(d) 1%

Open

Question.  21

The sum which will earn a simple interest of ₹ 126 in 2 years at 14% per annum is

(a)

(a) ₹ 394

(b)

(b) ₹ 395

(c)

(c) ₹ 450

(d)

(d) ₹ 540

Open

Question.  22

The per cent that represents the unshaded region in the figure.

(a)

(a) 75%

(b)

(b) 50%

(c)

(c) 40%

(d)

(d) 60%

Open

Question.  23

The per cent that represents the shaded region in the figure is

(a)

(a) 36%

(b)

(b) 64%

(c)

(c) 27%

(d)

(d) 48%

Open

Fill in the Blanks

In each of the questions 24 to 59, fill in the blanks to make the statements true.

Question. 24

2 : 3 = ______ %

Answer:

2 : 3 = 66 2/3 %

Open

Question. 25

18 3/4 % = ______ : ______

Answer:

18 3/4 % = 3 : 16

Open

Question. 26

30% of ₹ 360 = ______

Answer:

30% of ₹ 360 = ₹ 108

Open

Question. 27

120 % of 50 km = ______

Answer:

120 % of 50 km = 60 km

Open

Question. 28

2.5 = ______ %

Answer:

2.5 = 250 %

Open

Question. 29

8/5 = ______ %

Answer:

8/5 = 160 %

Open

Question. 30

A ______ with its denominator 100 is called a per cent.

Answer:

A fraction with its denominator 100 is called a per cent.

Open

Question. 31

15 kg is ______ % of 50 kg.

Answer:

15 kg is 30 % of 50 kg.

Open

Question. 32

Weight of Nikhil increased from 60 kg to 66 kg. Then, the increase in weight is ______ %.

Answer:

The increase in weight is 10 %.

Open

Question. 33

In a class of 50 students, 8% were absent on one day. The number of students present on that day was ______.

Answer:

The number of students present was 46.

Open

Question. 34

Savitri obtained 440 marks out of 500 in an examination. She secured ______ % marks in the examination.

Answer:

She secured 88 % marks.

Open

Question. 35

Out of a total deposit of ₹ 1500 in her bank account, Abida withdrew 40% of the deposit. Now the balance in her account is ______.

Answer:

The balance is ₹ 900.

Open

Question. 36

______ is 50% more than 60.

Answer:

90 is 50% more than 60.

Open

Question. 37

John sells a bat for ₹ 75 and suffers a loss of ₹ 8. The cost price of the bat is ______.

Answer:

The cost price is ₹ 83.

Open

Question. 38

If the price of sugar is decreased by 20%, then the new price of 3 kg sugar originally costing ₹ 120 will be ______.

Answer:

The new price will be ₹ 96.

Open

Question. 39

Mohini bought a cow for ₹ 9000 and sold it at a loss of ₹ 900. The selling price of the cow is ______.

Answer:

The selling price is ₹ 8100.

Open

Question. 40

Devangi buys a chair for ₹ 700 and sells it for ₹ 750. She earns a profit of ______ % in the transaction.

Answer:

She earns a profit of 7 1/7 %.

Open

Question. 41

Sonal bought a bed sheet for ₹ 400 and sold it for ₹ 440. Her ______% is ______.

Answer:

Her Profit % is 10.

Open

Question. 42

Nasim bought a pen for ₹ 60 and sold it for ₹ 54. His ______% is ______.

Answer:

His Loss % is 10.

Open

Question. 43

Aahuti purchased a house for ₹ 50,59,700 and spent ₹ 40,300 on its repairs. To make a profit of 5%, she should sell the house for ₹ ______.

Answer:

She should sell the house for ₹ 53,55,000.

Open

Question. 44

If 20 lemons are bought for ₹ 10 and sold at 5 for three rupees, then ______ in the transaction is ______%.

Answer:

Profit in the transaction is 20%.

Open

Question. 45

Narain bought 120 oranges at ₹ 4 each. He sold 60% of the oranges at ₹ 5 each and the remaining at ₹ 3.50 each. His ______ is ______%.

Answer:

His Profit is 10%.

Open

Question. 46

A fruit seller purchased 20 kg of apples at ₹ 50 per kg. Out of these, 5% were rotten. If he sells the remaining apples at ₹ 60 per kg, then his ______ is ______%.

Answer:

His Profit is 14%.

Open

Question. 47

Interest on ₹ 3000 at 10% per annum for a period of 3 years is ______.

Answer:

Interest = ₹ 900.

Open

Question. 48

Amount obtained by depositing ₹ 20,000 at 8% per annum for six months is ______.

Answer:

Amount = ₹ 20,800.

Open

Question. 49

Interest on ₹ 12500 at 18% per annum for a period of 2 years and 4 months is ______.

Answer:

Interest = ₹ 5250.

Open

Question. 50

25 ml is ______ per cent of 5 litres.

Answer:

25 ml is 0.5 per cent of 5 litres.

Open

Question. 51

If A is increased by 20%, it equals B. If B is decreased by 50%, it equals C. Then ______% of A is equal to C.

Answer:

60% of A is equal to C.

Open

Question. 52

Interest = (P × R × T) / 100, where T is __________, R% is __________ and P is __________.

Answer:

T is Time period, R% is Rate of Interest and P is Principal.

Open

Question. 53

The difference of interest for 2 years and 3 years on a sum of ₹ 2100 at 8% per annum is ______.

Answer:

The difference is ₹ 168.

Open

Question. 54

To convert a fraction into a per cent, we ______ it by 100.

Answer:

We Multiply it by 100.

Open

Question. 55

To convert a decimal into a per cent, we shift the decimal point two places to the ______.

Answer:

We shift the decimal point two places to the Right.

Open

Question. 56

The ______ of interest on a sum of ₹ 2000 at the rate of 6% per annum for 1 1/2 years and 2 years is ₹ 420.

Answer:

The Sum of interest is ₹ 420.

Open

Question. 57

When converted into percentage, the value of 6.5 is ______ than 100%.

Answer:

The value of 6.5 is More than 100%.

Open

Question. 58

Copy the number line. Fill in the blanks so that each mark is labelled with a per cent, a fraction and a decimal. Write all fractions in lowest terms.

Answer:

Attached sheet.

Open

Question. 59

Copy the number line. Fill in the blanks so that each mark is labelled with a per cent, a fraction and a decimal. Write all fractions in lowest terms.

Answer:

Attached sheet.

Open

True or False

In questions 60 to 79, state whether the statements are True or False.

Question. 60

\(\dfrac{2}{3} = 66\dfrac{2}{3}\%\).

Answer:

true

Open

Question. 61

When an improper fraction is converted into percentage then the answer can also be less than 100.

Answer:

false

Open

Question. 62

8 hours is 50% of 4 days.

Answer:

false

Open

Question. 63

The interest on ₹ 350 at 5% per annum for 73 days is ₹ 35.

Answer:

false

Open

Question. 64

The simple interest on a sum of ₹ P for T years at R% per annum is given by the formula: \(\dfrac{T \times P \times R}{100}\).

Answer:

true

Open

Question. 65

75% = \(\dfrac{4}{3}\).

Answer:

false

Open

Question. 66

12% of 120 is 100.

Answer:

false

Open

Question. 67

If Ankita obtains 336 marks out of 600, then percentage of marks obtained by her is 33.6.

Answer:

false

Open

Question. 68

0.018 is equivalent to 8%.

Answer:

false

Open

Question. 69

50% of ₹ 50 is ₹ 25.

Answer:

true

Open

Question. 70

250 cm is 4% of 1 km.

Answer:

false

Open

Question. 71

Out of 600 students of a school, 126 go for a picnic. The percentage of students that did not go for the picnic is 75.

Answer:

false

Open

Question. 72

By selling a book for ₹ 50, a shopkeeper suffers a loss of 10%. The cost price of the book is ₹ 60.

Answer:

false

Open

Question. 73

If a chair is bought for ₹ 2000 and is sold at a gain of 10%, then selling price of the chair is ₹ 2010.

Answer:

false

Open

Question. 74

If a bicycle was bought for ₹ 650 and sold for ₹ 585, then percentage of profit is 10.

Answer:

false

Open

Question. 75

Sushma sold her watch for ₹ 3320 at a gain of ₹ 320. For earning a gain of 10% she should have sold the watch for ₹ 3300.

Answer:

true

Open

Question. 76

Interest on ₹ 1200 for 1 1/2 years at the rate of 15% per annum is ₹ 180.

Answer:

false

Open

Question. 77

Amount received after depositing ₹ 800 for a period of 3 years at the rate of 12% per annum is ₹ 896.

Answer:

false

Open

Question. 78

₹ 6400 were lent to Feroz and Rashmi at 15% per annum for 3 1/2 and 5 years respectively. The difference in the interest paid by them is ₹ 150.

Answer:

false

Open

Question. 79

A vendor purchased 720 lemons at ₹ 120 per hundred. 10% of the lemons were found rotten which he sold at ₹ 50 per hundred. If he sells the remaining lemons at ₹ 125 per hundred, then his profit will be 16%.

Answer:

false

Open

Problems and Solutions

In Questions 80 to 107, solve each problem and provide the reasoning as required.

Question. 80

Find the value of x if

(i) 8% of ₹ x is ₹ 100

(ii) 32% of x kg is 400 kg

(iii) 35% of ₹ x is ₹ 280

(iv) 45% of marks x is 405

Answer:

(i) 1250

(ii) 1250

(iii) 800

(iv) 900

Open

Question. 81

Imagine that a 10 × 10 grid has value 300 and that this value is divided evenly among the small squares. In other words, each small square is worth 3. Use a new grid for each part of this problem, and label each grid “Value : 300.”

(a) Shade 25% of the grid. What is 25% of 300? Compare the two answers.

(b) What is the value of 25 squares?

(c) Shade 17% of the grid. What is 17% of 300? Compare the two answers.

(d) What is the value of 1/10 of the grid?

Answer:

(a) 75

(b) 75

(c) 17; 51

(d) 30

Open

Question. 82

Express 1/6 as a per cent.

Answer:

16.6% or 50/3%

Open

Question. 83

Express 9/40 as a per cent.

Answer:

22 1/2%

Open

Question. 84

Express 1/100 as a per cent.

Answer:

1%

Open

Question. 85

Express 80% as fraction in its lowest term.

Answer:

4/5

Open

Question. 86

Express 33 1/3% as a ratio in the lowest term.

Answer:

1 : 3

Open

Question. 87

Express 16 2/3% as a ratio in the lowest form.

Answer:

1 : 6

Open

Question. 88

Express 150% as a ratio in the lowest form.

Answer:

3 : 2

Open

Question. 89

Sachin and Sanjana are calculating 23% of 800.

Answer:

364

Open

Question. 90

Write 0.089 as a per cent.

Answer:

8.9%

Open

Question. 91

Write 1.56 as a per cent.

Answer:

156%

Open

Question. 92

What is 15% of 20?

Answer:

3

Open

Question. 93

What is 800% of 800?

Answer:

6400

Open

Question. 94

What is 100% of 500?

Answer:

500

Open

Question. 95

What per cent of 1 hour is 30 minutes?

Answer:

50%

Open

Question. 96

What per cent of 1 day is 1 minute?

Answer:

0.069%

Open

Question. 97

What per cent of 1 km is 1000 metres?

Answer:

100%

Open

Question. 98

Find out 8% of 25 kg.

Answer:

2 kg

Open

Question. 99

What percent of ₹ 80 is ₹ 100?

Answer:

125%

Open

Question. 100

45% of the population of a town are men and 40% are women. What is the percentage of children?

Answer:

15%

Open

Question. 101

The strength of a school is 2000. If 40% of the students are girls then how many boys are there in the school?

Answer:

1200

Open

Question. 102

Chalk contains 10% calcium, 3% carbon and 12% oxygen. Find the amount of carbon and calcium (in grams) in 2 1/2 kg of chalk.

Answer:

Carbon = 75 g, Calcium = 250 g

Open

Question. 103

800 kg of mortar consists of 55% sand, 33% cement and rest lime. What is the mass of lime in mortar?

Answer:

96 kg

Open

Question. 104

In a furniture shop, 24 tables were bought at the rate of ₹ 450 per table. The shopkeeper sold 16 of them at the rate of ₹ 600 per table and the remaining at the rate of 400 per table. Find her gain or loss percent.

Answer:

Gain of 18.5%

Open

Question. 105

Medha deposited 20% of her money in a bank. After spending 20% of the remainder, she has ₹ 4800 left with her. How much did she originally have?

Answer:

₹ 7500

Open

Question. 106

The cost of a flower vase got increased by 12%. If the current cost is ₹ 896, what was its original cost?

Answer:

₹ 800

Open

Question. 107

Radhika borrowed ₹ 12000 from her friends. Out of which ₹ 4000 were borrowed at 18% and the remaining at 15% rate of interest per annum. What is the total interest after 3 years?

Answer:

₹ 5760

Open

Question. 108

A man travelled 60 km by car and 240 km by train. Find what per cent of total journey did he travel by car and what per cent by train?

Answer:

20% by Car, 80% by Train

Open

Question. 109

By selling a chair for ₹ 1440, a shopkeeper loses 10%. At what price did he buy it?

Answer:

₹ 1600

Open

Question. 110

Dhruvika invested money for a period from May 2006 to April 2008 at rate of 12% per annum. If interest received by her is ₹ 1620, find the money invested.

Answer:

₹ 6750

Open

Question. 111

A person wanted to sell a scooter at a loss of 25%. But at the last moment he changed his mind and sold the scooter at a loss of 20%. If the difference in the two SP’s is ₹ 4000, then find the CP of the scooter.

Answer:

₹ 80,000

Open

Question. 112

The population of a village is 8000. Out of these, 80% are literate and of these literate people, 40% are women. Find the ratio of the number of literate women to the total population.

Answer:

8 : 25

Open

Question. 113

In an entertainment programme, 250 tickets of ₹ 400 and 500 tickets of ₹ 100 were sold. If the entertainment tax is 40% on ticket of ₹ 400 and 20% on ticket of ₹ 100, find how much entertainment tax was collected from the programme.

Answer:

₹ 50,000

Open

Question. 114

Bhavya earns ₹ 50,000 per month and spends 80% of it. Due to pay revision, her monthly income increases by 20% but due to price rise, she has to spend 20% more. Find her new savings.

Answer:

₹ 12,000

Open

Question. 115

In an examination, there are three papers each of 100 marks. A candidate obtained 53 marks in the first and 75 marks in the second paper. How many marks must the candidate obtain in the third paper to get an overall of 70 per cent marks?

Answer:

82

Open

Question. 116

Health Application: A doctor reports blood pressure... Refer to the table of blood pressure ranges for adults. Manohar is in the normal category.

(a) Calculate an approximate ratio of systolic to diastolic blood pressures in the normal range.

(b) If Manohar’s systolic blood pressure is 102 mm Hg, use the ratio from part (a) to predict his diastolic blood pressure.

(c) Calculate ratio of average systolic to average diastolic blood pressure in the prehypertension category.

Answer:

(a) 3 : 2

(b) 68 mm Hg

(c) 259 : 169

Open

Question. 117

(a) Science Application: The king cobra can reach a length of 558 cm. This is only about 60% of the length of the largest reticulated python. Find the length of the largest reticulated python.

(b) Physical Science Application: Unequal masses... If mass1 = 24 kg at 3 m and length2 = 2 m, find mass of child on right.

(c) Life Science Application: A DNA model was built using the scale 2 cm : 0.0000001 mm. If the model of the DNA chain is 17 cm long, what is the length of the actual chain?

Answer:

(a) 9300 cm

(b) 36 kg

(c) 0.000000085 mm

Open

Question. 118

Language Application: Given below are few Mathematical terms: Hypotenuse, Congruence, Perpendicular, Transversal, Correspondence.

(a) Find the ratio of consonants to vowels in each of the terms.

(b) Find the percentage of consonants in each of the terms.

Answer:

(a) 3:2, 3:2, 8:3, 8:3, 9:5

(b) 60%, 60%, 61.53%, 72.72%, 64.28%

Open

Question. 119

What's the Error? An analysis showed that 0.06% of the T-shirts made by one company were defective. A student says this is 6 out of every 100. What is the student's error?

Answer:

6/10000

Open

Question. 120

What's the Error? A student said that the ratios 3/4 and 9/16 were proportional. What error did the student make?

Answer:

48 ≠ 36

Open

Question. 121

What's the Error? A clothing store charges ₹ 1024 for 4 T-shirts. A student says that the unit price is ₹ 25.6 per T-shirt. What is the error? What is the correct unit price?

Answer:

₹ 256

Open

Question. 122

A tea merchant blends two varieties of tea in the ratio of 5 : 4. The cost of first variety is ₹ 200 per kg and that of second variety is ₹ 300 per kg. If he sells the blended tea at the rate of ₹ 275 per kg, find out the percentage of her profit or loss.

Answer:

12.5%

Open

Question. 123

A piece of cloth 5 m long shrinks 10 per cent on washing. How long will the cloth be after washing?

Answer:

4.5 m

Open

Question. 124

Nancy obtained 426 marks out of 600 and the marks obtained by Rohit are 560 out of 800. Whose performance is better?

Answer:

Nancy

Open

Question. 125

A memorial trust donates ₹ 5,00,000 to a school, the interest on which is to be used for awarding 3 scholarships to students obtaining first three positions in the school examination every year. If the donation earns an interest of 12% per annum and the values of the second and third scholarships are ₹ 20,000 and ₹ 15,000 respectively, find out the value of the first scholarship.

Answer:

₹ 25,000

Open

Question. 126

Ambika got 99 per cent marks in Mathematics, 76 per cent marks in Hindi, 61 per cent in English, 84 per cent in Science, and 95% in Social Science. If each subject carries 100 marks, then find the percentage of marks obtained by Ambika in the aggregate of all the subjects.

Answer:

Percentage of marks = 83%

Open

Question. 127

What sum of money lent out at 16 per cent per annum simple interest would produce ₹ 9600 as interest in 2 years?

Answer:

The sum of money = ₹ 30,000

Open

Question. 128

Harish bought a gas-chullah for ₹ 900 and later sold it to Archana at a profit of 5 per cent. Archana used it for two years and later sold it to Babita at a loss of 20 per cent. For how much did Babita get it?

Answer:

Babita bought it for ₹ 756

Open

Question. 129

Match each of the entries in Column I with the appropriate entries in Column II:

Column IColumn II
(i) 3:5(A) ₹ 54
(ii) 2.5(B) ₹ 47
(iii) 100%(C) ₹ 53
(iv) 2/3(D) ₹ 160
(v) 6¼%(E) 60%
(vi) 12.5%(F) 25%
(vii) SP when CP = ₹ 50 and loss = 6%(G) 1/16
(viii) SP when CP = ₹ 50 and profit = ₹ 4(H) 250%
(ix) Profit% when CP = ₹ 40 and SP = ₹ 50(I) ₹ 159
(x) Profit% when CP = ₹ 50 and SP = ₹ 60(J) 66⅔%
(xi) Interest when principal = ₹ 800, rate = 10% per annum, period = 2 years(K) 20%
(xii) Amount when principal = ₹ 150, rate = 6% per annum, period = 1 year(L) 0.125

Answer:

(i) ↔ E, (ii) ↔ H, (iii) ↔ O, (iv) ↔ J, (v) ↔ G, (vi) ↔ L, (vii) ↔ B, (viii) ↔ A, (ix) ↔ F, (x) ↔ K, (xi) ↔ D, (xii) ↔ I

Open

Question. 130

In a debate competition, the judges decide that 20 per cent of the total marks would be given for accent and presentation. 60 per cent of the rest are reserved for subject matter and the rest for rebuttal. If this means 8 marks for rebuttal, then find the total marks.

Answer:

Total marks = 25

Open

Question. 131

Divide ₹ 10000 in two parts so that the simple interest on the first part for 4 years at 12% per annum equals the simple interest on the second part for 4.5 years at 16% per annum.

Answer:

The two parts are ₹ 6000 and ₹ 4000

Open

Question. 132

₹ 9000 becomes ₹ 18000 at simple interest in 8 years. Find the rate of interest per annum.

Answer:

Rate = 12.5%

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Question. 133

In how many years will the simple interest on a certain sum be 4.05 times the principal at 13.5% per annum?

Answer:

Time = 30 years

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Question. 134

The simple interest on a certain sum for 8 years at 12% per annum is ₹ 3120 more than the simple interest on the same sum for 5 years at 14% per annum. Find the sum.

Answer:

Sum = ₹ 12,000

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Question. 135

The simple interest on a certain sum for 2.5 years at 12% per annum is ₹ 300 less than the simple interest on the same sum for 4.5 years at 8% per annum. Find the sum.

Answer:

Sum = ₹ 5,000

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Question. 136

Designing a Healthy Diet: Answer the given questions.

Answer:

(1) Your ideal desired weight is 40 kg.
(2) The quantity of calories you need is 2204.4.
(3) The quantity of protein needed is 82.66 g.
(4) The quantity of fat required is 73.47 g.
(5) The quantity of carbohydrates required is 300 g.

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Question. 137

150 students are studying English, Maths or both. 62% study English and 68% study Maths. How many are studying both?

Answer:

45 students

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Question. 138

Earth Science: Refer table of world’s largest deserts. Answer:

(a) What are the mean, median and mode of the areas listed?
(b) How many times the size of the Gobi Desert is the Namib Desert?
(c) What percentage of deserts listed are in Asia?
(d) What percentage of total area is in Asia?

Answer:

(a) Mean = 14,35,000 km², Median = 4,75,000 km², Mode = 3,10,000 km².
(b) 4.19 times.
(c) 50%.
(d) 21.1%.

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Question. 139

Geography Application: Earth’s total land = 148428950 km². Asia’s land = 30% of this. Find approximate land area of Asia.

Answer:

Asia’s land area = 44,52,86,85 km²

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Question. 140

Tangram: Find percentage of each color.

Answer:

Red = 37.5%, Blue = 12.5%, Green = 50%

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NCERT Exemplar Solutions Class 7 – Mathematics – Unit 7: Comparing Quantities | Detailed Answers